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Audio "pops"/"ticks"/"crackling" at the beginning of clips

maartenb
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Dear forum,

I've used Kdenlive for several serious projects. I love Kdenlive; it's by far the best NLE for me, so thanks devs!

Yesterday I rendered a new project. To my surprise there were audio artifacts in the render. It sounds like "clicks", "pops" or "ticks". I will call them "clicks" in the rest of this post.

After investigation, it turned out that the clicks happen at the beginning of each clip. The click sounds about one second after the start of a clip. A second click is heard half a second after that. It doesn't matter whether it's a video clip or an audio clip.

The clicks sound during editing and also in the rendered file.

I've had this problem in the past (Kdenlive 17.04 (??)). I don't remember exactly what I did then to solve it, but I vaguely remember installing a more recent version of MLT. Since I am already on MLT 6.5.0, I can't upgrade that.

Other posts about this subject on this forum are: https://forum.kde.org/viewtopic.php?f=271&t=143448 and https://forum.kde.org/viewtopic.php?f=265&t=139736&hilit=audio+crackling. Both don't have an answer.

The clicks are not in the source audio. Sometimes the click are not there, but most of the time they are. I use a video clip with audio, and a background music audio clip with gain at 20%. The combined audio of the video clip and audio clip do not exceed 0dB, so no clipping is taking place.

I use Kubuntu 17.10. The clicks are in Kdenlive 17.12.0 which is bundled with Kubuntu 17.10. It also happens with the most recent Kdenlive AppImage 17.12.0d.

I am at a loss.

Any help is greatly appreciated! Thanks in advance!!


Maarten
maartenb
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In the meantime I did some testing with other versions of KDEnlive using the AppImages.

  • 17.08.3 - Render aborts with message "Rendering of "path/file.mp4" aborted, resulting video will probably be corrupted." The video file is way too small and not playable.
  • 17.04.1b - This version cannot read the .kdenlive file, saying it can't read this version.

My ideas for potential workarounds have failed so far, and I am out of ideas.

This means I cannot use KDEnlive anymore, until it is fixed. :(

I hope the developers find the cause of the bug soon.


Maarten
maartenb
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I just tried another idea: to render only to audio and to later merge that with the video.

Unfortunately, rendering to audio only gives the same audio artifacts, the same cracks and ticks.


Maarten

P.S. A new version of MLT (6.6.0) was released about a week ago. Now I will figure out how I can install that from git into Kubuntu 17.10.
maartenb
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To make sure my Kubuntu installation wasn't the source of the problem, I used VirtualBox to install a fresh, latest KDE Neon iso, installed Kdenlive in it and rendered my project to .wav audio only.

The exact same audio ticks appear in the render.

I noticed something else, too. The audio balance was changed (the volumes of clips and tracks). Some fade ins and fade outs did not sound as they should be.

Maybe there's a problem with the Audio Gain plugin, or the Fade in/out plugin?


Maarten
Stetsbequem
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maartenb wrote:The clicks are not in the source audio.

In general. It is quite exciting to find out which systems and versions each one of you uses, but if there are problems with the processing of the sound, it would be helpful to find out in which format it is in (codec, container, lossless or compressed). To make it clear: Unlike a DAW, the audio track is not converted to an internal format and replaced by it, but only an index is created.


Either you choose the right job for the tool, or the right tool for the job.
maartenb
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Stetsbequem wrote:it would be helpful to find out in which format it is in

Thanks for your help.

I combine three audio sources:
  1. The audio from my video clips
    These are recorded with a Panasonic Lumix FZ1000, which uses .mp4 as container and AAC 44.1kHz for audio. I can't see the bit depth in Kdenlive.
  2. Voice-over
    These are recorded in .wav (PCM signed) format, 44.1kHz, 24 bit.
  3. Background music
    Recorded as .wav (PCM signed) format, 44.1kHz, 16 bit.

Turning off the background music track doesn't do anything for the ticks; they are still there. The ticks sound at the beginning of most voice-over clips (not all, strangely enough).

Each voice-over clip has fade-in and fade-out (but the ticks are audible outside the fade areas, so after when the fade-in is complete), and each voice-over clip has an Audio Gain effect set at 185%, because the volume was much too low. The audio is not clipping after the Gain, since the ticks sound very different from clipping audio artifacts.


Maarten
mentil
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I feel your pain. Did you ever successfully update to MLT 6.6.0? Your problem sounds similar to mine, which I made a new post (in the rendering codecs subforum) for so as to not hijack your thread. I found a workaround, so you may want to read it.
Stetsbequem
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This is probably a bug in the Kdenlive/MLT team, who claim to be able to handle any of the compressed codecs in the video editing. I have already written down my view of the montage with compressed material, here. With compressed formats, there are too many construction sites for troubleshooting, so you don't know where to start.

Maybe someone else will be able to help you make the short walk. You may be helped by the
process of elimination. To do this, you create a new temporary project and check each file individually for its suitability. But this is just as time-consuming as converting it into a cuttable material. In addition, these problems occur sporadically, one cannot be sure at present.

And it's probably worth knowing that a track muted in Kdenlive isn't necessarily muted and a video deleted from the track isn't necessarily removed. The colleague also describes this in his very long Workaround. (In my opinion, the better workaround would be to use an editor that does not have such problems, such as Cinelerra CGG. You can switch back to a stable version of Kdenlive later on, when it is finished. Don't let yourself be faded out by the 17 in the version, this is just the date of compilation appropriate to KDE, it doesn't say anything about the suggested high level of development.) Good luck.


Either you choose the right job for the tool, or the right tool for the job.
maartenb
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Today I received Kdenlive 17.12.3 from the Kubuntu repositories. This uses MLT 6.5.0.

The ticks/pops/clicks are still there when playing my project from the timeline.

The workaround offered in the other thread by Mentil did not work for me.

I have a suspicion that the ticks appear in audio clips that are recorded in 24 bits. These clips are mixed with a background audio track of 16 bits.


Maarten
maartenb
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Recently I did a test with the Kdenlive 17.18.04 AppImage. This version uses MLT 6.7.0.

The audio ticks are still present. :(

As a workaround, I do all my new audio recordings in 16 bit now. I've edited a few small projects in 18.04.0 with these 16 bit audio tracks and that works reliable.


Maarten
ADepic
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Import clip into project bin > Right click on audio file (or video file) > Extract Audio > WAV 48000Hz > save as new wav file.

I guarantee this will work.
luppa
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I guess I could chime in on this... I just edited with Kdenlive the first video I actually kinda "published", a demo of a guitar distortion pedal I made. I did a render with the MP4 preset and uploaded it to Youtube, and then heard the sort of ticks and crackling sound described in this thread. Dusty vinyl is a good analog. At first I blamed Youtube and it's re-encoding, but then noticed that the crackling was already in the rendered file. It was not that obvious at first, especially when it's on top of an already "crackly" guitar sound.

I used Kdenlive 18.08.2 with Win7 (I still can't find the .3 for Windows. Where is it?). All other audio is muted other than two 16bit stereo 44100 .wav files, straight outta Reaper. The wav files are not mostly playing on top of each other, but there is a small part where the other one fades out and the other one fades in. Unlike at the topic of the thread, the crackling does not seem to be connected to beginning of clips, or to transitions or anything else I can think of.

I rendered a second time with the WEBM preset, and the crackling was gone. I also did a MKV preset myself with h264 video and ogg audio, and there's no crackling in a video rendered with that one either.
dhealey
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Hi,

I've just hit this problem. I have 2 audio tracks, one is background music the other is foley. Everytime something on the foley track plays it makes a click happen (I use fade in/outs for every clip). This only occurs in a rendered file (I've tried all formats of video and audio) it doesn't occur in the timeline preview.

If I export the foley track by itself there is no problem, same if I export the music track on its own.

I'm using kdenlive-19.04.2f-x86_64 app image on Linux Mint. All the audio files I'm using are .mp3 44.1khz

I have opened a section of the rendered audio in a spectrogram and the clicks are clearly visible.
Image
Merlimau
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I tested with 2 different Mp3 44.1khz files as you descript on Windows 19.04.2-5 and Appimage 19.04.2f. On the MP4 render file I have no clicks. Which mp3 is on which audio track? Could you upload both Mp3 files somewhere that I can test?
dhealey
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Merlimau wrote:I tested with 2 different Mp3 44.1khz files as you descript on Windows 19.04.2-5 and Appimage 19.04.2f. On the MP4 render file I have no clicks. Which mp3 is on which audio track? Could you upload both Mp3 files somewhere that I can test?


Hi,

I've uploaded the files to dropbox here. There is a screenshot included so you can see which tracks use which files, but only portions of some of the files are used so it's difficult for me to share the setup exactly as I have it without sharing my entire project (unless you know another way).

The only audio tracks that were used when I made my previous post are A2 and A7, so you can ignore the rest that are shown in the screenshot.

 
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